diff --git a/ChangeLog b/ChangeLog
index 68a25ba2..ea829baa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2009-04-11  Nicolas François  <nicolas.francois@centraliens.net>
+
+	* libmisc/getgr_nam_gid.c: Added support for NULL argument.
+	* libmisc/chowntty.c: Reuse getgr_nam_gid(), and get rid of atol().
+
 2009-04-11  Peter Vrabec  <pvrabec@redhat.com>
 
 	* libmisc/find_new_gid.c, libmisc/find_new_uid.c: For system
diff --git a/libmisc/chowntty.c b/libmisc/chowntty.c
index 3d4da107..6b97ab76 100644
--- a/libmisc/chowntty.c
+++ b/libmisc/chowntty.c
@@ -2,7 +2,7 @@
  * Copyright (c) 1989 - 1994, Julianne Frances Haugh
  * Copyright (c) 1996 - 2001, Marek Michałkiewicz
  * Copyright (c) 2003 - 2005, Tomasz Kłoczko
- * Copyright (c) 2007 - 2008, Nicolas François
+ * Copyright (c) 2007 - 2009, Nicolas François
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -51,7 +51,6 @@
 
 void chown_tty (const struct passwd *info)
 {
-	char *group;		/* TTY group name or number */
 	struct group *grent;
 	gid_t gid;
 
@@ -60,18 +59,11 @@ void chown_tty (const struct passwd *info)
 	 * ID.  Otherwise, use the user's primary group ID.
 	 */
 
-	group = getdef_str ("TTYGROUP");
-	if (NULL == group) {
-		gid = info->pw_gid;
-	} else if ((group[0] >= '0') && (group[0] <= '9')) {
-		gid = (gid_t) atol (group);
+	grent = getgr_nam_gid (getdef_str ("TTYGROUP"));
+	if (NULL != grent) {
+		gid = grent->gr_gid;
 	} else {
-		grent = getgrnam (group); /* local, no need for xgetgrnam */
-		if (NULL != grent) {
-			gid = grent->gr_gid;
-		} else {
-			gid = info->pw_gid;
-		}
+		gid = info->pw_gid;
 	}
 
 	/*
diff --git a/libmisc/getgr_nam_gid.c b/libmisc/getgr_nam_gid.c
index 7120304c..5398a2d9 100644
--- a/libmisc/getgr_nam_gid.c
+++ b/libmisc/getgr_nam_gid.c
@@ -49,6 +49,10 @@ extern struct group *getgr_nam_gid (const char *grname)
 	long long int gid;
 	char *endptr;
 
+	if (NULL == grname) {
+		return NULL;
+	}
+
 	errno = 0;
 	gid = strtoll (grname, &endptr, 10);
 	if (   ('\0' != *grname)